Severe inflammatory disease activity 14 months after cessation of Natalizumab in a patient with Leber’s optic neuropathy and multiple sclerosis – a case report

BACKGROUND Leber's hereditary optic neuropathy (LHON) co-occuring with multiple sclerosis-like disease (LHON-MS) is suggested to be a separate disease entity denoted Harding's disease. Little is known about the response to initiation and discontinuation of potent immunomodulatory treatment in LHON-MS. CASE PRESENTATION We describe a LHON-MS patient with 27 years disease duration who developed severe disease activity peaking 14 months after discontinuation of natalizumab, with extensive new inflammatory lesions throughout the brain and in the spinal cord resembling immune inflammatory reconstitution syndrome. She had previously been clinically and radiologically stable on natalizumab treatment for 6 years, and before that only experienced subtle clinical activity during 9 years on interferon beta1a. CONCLUSION This is the first report on severe exacerbation of inflammatory disease activity after discontinuation of natalizumab in LHON-MS, and suggests that late rebound activity can occur in these patients.